1. Field of the Invention
The present invention relates to a molding mold and a molding method for molding a flange configuration, and a tape cartridge.
2. Description of the Prior Art
A one-reel-type cartridge is provided with a reel hub portion having an upper flange and a lower flange at an inside of the cartridge. A tape-shaped recording medium is wound around the hub portion, which is used for storing back-up data for a computer or the like. When the tape cartridge is mounted to a magnetic recording and reproducing apparatus for a computer, the tape-shaped recording medium wound around a hub of an internal reel hub portion is made to be drawn out, and thereafter wound around a reel hub portion at the side of the magnetic recording and reproducing apparatus, so that the tape-shaped recording medium runs between both the hubs, and recording or reproducing are performed. Also, a magnetic plate is attached to a center of the lower flange of the reel hub portion by insert molding, resulting in securely establishing engagement between the reel hub and a driving portion at the side of the magnetic recording and reproducing apparatus.
When such a tape cartridge is mounted to a magnetic recording and reproducing apparatus for a computer and used for storing back-up data, it is required that the tape-shaped recording medium runs, touching at the recording and reproducing head of the apparatus by maintaining an extraordinarily high accuracy as to the positioning.
However, when the reel hub portion of the tape cartridge is produced by molding the lower flange and the hub integrally, the lower flange may be deformed apart from a predetermined configuration, resulting in that there is possibility that upon using the tape cartridge, an under end of a running tape-shaped recording medium might extraordinarily approach toward an inside surface of the lower flange, so that there is possibility that the under end and the inside surface might mutually be touched. If such a touching state happen, there might occur any problem upon recording and reproducing by the recording and reproducing head with relative to the tape-shaped recording medium. Therefore, it is required that the above-mentioned possibility does not occur.